Apache Ignite 2.x - can I take advantage of offheap storage and also still have time based eviction (from the on & off heap storage)?

0
votes

I am using Apache Ignite 2.8.1

I have a specific cache that I need to store off heap (because otherwise I will be plagued with out of memory conditions). And I also need the cache to be distributed.

But I also want a time based eviction policy to evict entries from on/off memory cache.

Is this even possible with Apache Ignite 2.x?

See the snippet here. I have tried to configure this every which way, but nothing evicts these entries from the cache except doing it manually.

When I run the test method below, all the entries remain in the cache.

import java.time.LocalDateTime;
import java.util.Arrays;
import java.util.concurrent.TimeUnit;

import javax.cache.expiry.CreatedExpiryPolicy;
import javax.cache.expiry.Duration;

import org.apache.ignite.Ignite;
import org.apache.ignite.Ignition;
import org.apache.ignite.cache.CacheAtomicityMode;
import org.apache.ignite.cache.CacheMode;
import org.apache.ignite.cache.eviction.lru.LruEvictionPolicyFactory;
import org.apache.ignite.configuration.CacheConfiguration;
import org.apache.ignite.configuration.DataRegionConfiguration;
import org.apache.ignite.configuration.DataStorageConfiguration;
import org.apache.ignite.configuration.IgniteConfiguration;
import org.apache.ignite.configuration.NearCacheConfiguration;
import org.apache.ignite.spi.discovery.tcp.TcpDiscoverySpi;
import org.apache.ignite.spi.discovery.tcp.ipfinder.vm.TcpDiscoveryVmIpFinder;
    
public class IgniteCache {
    private static final String ORG_CACHE = IgniteCache.class.getSimpleName() + "Organizations";

    private static Ignite ignite;
    
    private static org.apache.ignite.IgniteCache cache;
    
    public void start() {

        IgniteConfiguration igniteConfiguration = new IgniteConfiguration();
        DataStorageConfiguration dsCfg = new DataStorageConfiguration();
        DataRegionConfiguration dfltDataRegConf = new DataRegionConfiguration();
        dfltDataRegConf.setPersistenceEnabled(true);
        dsCfg.setDefaultDataRegionConfiguration(dfltDataRegConf);
        dsCfg.setStoragePath("E:\\igniteStorage");
        igniteConfiguration.setDataStorageConfiguration(dsCfg);

        TcpDiscoverySpi tcpDiscoverySpi = new TcpDiscoverySpi();
        TcpDiscoveryVmIpFinder ipFinder = new TcpDiscoveryVmIpFinder();
        ipFinder.setAddresses(Arrays.asList("127.0.0.1:47500..47509"));
        tcpDiscoverySpi.setIpFinder(ipFinder);

        igniteConfiguration.setDiscoverySpi(tcpDiscoverySpi);

        ignite = Ignition.start(igniteConfiguration);
        
        ignite.active(true);

        CacheConfiguration<Long, X12File> cacheCfg = new CacheConfiguration<>(ORG_CACHE);

        cacheCfg.setCacheMode(CacheMode.REPLICATED);
        cacheCfg.setAtomicityMode(CacheAtomicityMode.ATOMIC);
        cacheCfg.setBackups(1);
        
        cacheCfg.setEvictionPolicyFactory(new LruEvictionPolicyFactory<>(50000, 40, 5050)); // this doesn't do anything.
        cacheCfg.setNearConfiguration(
                new NearCacheConfiguration<Long, X12File>()
                .setNearEvictionPolicyFactory(new LruEvictionPolicyFactory<>(1_000_000))); // this doesn't do anything.
        
        cache = ignite.getOrCreateCache(cacheCfg);      
        
        for (long i = 0; i < 4_000_000; i++) {
            if (i > 0 && i % 10_000 == 0) {
                System.out.println("Done: " + i);
            }
            cache.withExpiryPolicy(new CreatedExpiryPolicy(new Duration(TimeUnit.SECONDS, 1))) // this expiry policy doesn't do anything
                .put(i, new X12File("x12file" + i, LocalDateTime.now().toString()));
        }
    }
    
    public void test() {
        System.out.println("Checking if cache entries are being properly evicted ...");

        int matches = 0;
        for (long i = 0; i < 4_000_000; i++) {
            if (cache.get(i) != null) {
                ++matches;
            }
        }
        System.out.println("Matches: " + matches);
    }   
}

Is this just a shortcoming of Apache Ignite 2.x in my particular use case?

2
javaignitedistributed-caching

2 Answers

1
votes

In short:

  • Eviction is memory-based. Remove some records because I have too many rows or it's using too much space
  • Expiry is time-based. This record hasn't been touched for a specified period of time, so it should be removed

All caches are off-heap. You can configure the expiry policy for a cache something like this:

<bean class="org.apache.ignite.configuration.CacheConfiguration">
    <property name="name" value="myCache"/>
    <property name="expiryPolicyFactory">
        <bean class="javax.cache.expiry.CreatedExpiryPolicy" factory-method="factoryOf">
            <constructor-arg>
                <bean class="javax.cache.expiry.Duration">
                    <constructor-arg value="MINUTES"/>
                    <constructor-arg value="5"/>
                </bean>
            </constructor-arg>
        </bean>
   </property>
</bean>

(The near/on-heap cache does do something. Just not what you were expecting! They're both on-heap and work in addition to the off-heap cache.)

1
votes

As I understand from your code and from your explanation, it looks like you are a little confused about the Eviction Policies and the Expiry Policies.

  1. Eviction policy determines which data should be removed from RAM if RAM runs out.
  2. Expiry policy using for determining TTL of cache entries.

In your case you need only Expiry policy. Look at my example:

private static final String ORG_CACHE = IgniteCache.class.getSimpleName() + "Organizations";

public static void main(String[] args) throws Exception {
    DataRegionConfiguration dfltDataRegConf = new DataRegionConfiguration();
    dfltDataRegConf.setPersistenceEnabled(true);

    DataStorageConfiguration dsCfg = new DataStorageConfiguration();
    dsCfg.setDefaultDataRegionConfiguration(dfltDataRegConf);
    dsCfg.setStoragePath("/home/kazakov/tmp");

    IgniteConfiguration igniteConfiguration = new IgniteConfiguration();
    igniteConfiguration.setDataStorageConfiguration(dsCfg);

    TcpDiscoverySpi tcpDiscoverySpi = new TcpDiscoverySpi();
    TcpDiscoveryVmIpFinder ipFinder = new TcpDiscoveryVmIpFinder();
    ipFinder.setAddresses(Arrays.asList("127.0.0.1:47500..47509"));
    tcpDiscoverySpi.setIpFinder(ipFinder);

    igniteConfiguration.setDiscoverySpi(tcpDiscoverySpi);

    try(Ignite ignite = Ignition.start(igniteConfiguration)) {
        ignite.active(true);

        CacheConfiguration<Long, X12File> cacheCfg = new CacheConfiguration<>(ORG_CACHE);

        cacheCfg.setCacheMode(CacheMode.REPLICATED);
        cacheCfg.setAtomicityMode(CacheAtomicityMode.ATOMIC);
        cacheCfg.setBackups(1);
        cacheCfg.setOnheapCacheEnabled(true);

        IgniteCache<Long, X12File> cache = ignite.getOrCreateCache(cacheCfg).withExpiryPolicy(new CreatedExpiryPolicy(new Duration(TimeUnit.SECONDS, 1)));

        for (long i = 0; i < 4_000_000; i++) {
            if (i > 0 && i % 10_000 == 0)
                System.out.println("Done: " + i);

            cache.put(i, new X12File("x12file" + i, LocalDateTime.now().toString()));
        }

        Thread.sleep(5000);

        int matches = 0;
        for (long i = 0; i < 4_000_000; i++) {
            if (cache.get(i) != null)
                ++matches;
        }
        System.out.println("Matches: " + matches);
    }
}